diff --git a/lib/Slic3r/GUI/Plater.pm b/lib/Slic3r/GUI/Plater.pm
index 4474550f58..9e61630fb2 100644
--- a/lib/Slic3r/GUI/Plater.pm
+++ b/lib/Slic3r/GUI/Plater.pm
@@ -1434,10 +1434,10 @@ sub reload_from_disk {
     return if !$model_object->input_file
         || !-e $model_object->input_file;
     
-    my @obj_idx = $self->load_file($model_object->input_file);
-    return if !@obj_idx;
+    my @new_obj_idx = $self->load_file($model_object->input_file);
+    return if !@new_obj_idx;
     
-    foreach my $new_obj_idx (@obj_idx) {
+    foreach my $new_obj_idx (@new_obj_idx) {
         my $o = $self->{model}->objects->[$new_obj_idx];
         $o->clear_instances;
         $o->add_instance($_) for @{$model_object->instances};
@@ -1450,6 +1450,12 @@ sub reload_from_disk {
     }
     
     $self->remove($obj_idx);
+    
+    # Trigger thumbnail generation again, because the remove() method altered
+    # object indexes before background thumbnail generation called its completion
+    # event, so the on_thumbnail_made callback is called with the wrong $obj_idx.
+    # When porting to C++ we'll probably have cleaner ways to do this.
+    $self->make_thumbnail($_-1) for @new_obj_idx;
 }
 
 sub export_object_stl {